U.S. patent application number 10/167199 was filed with the patent office on 2003-02-20 for process for the treatment of industrial effluents using marine algae to produce potable water.
This patent application is currently assigned to COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH (AN INDIAN REGISTERED BODY INCORPORATED UNDER. Invention is credited to Dhargalkar, Vinod Kashinath, Moghe, Pramod Prabhakar, Panchanadikar, Vinita Vinay, Untawale, Arvind Gajanan.
Application Number | 20030034299 10/167199 |
Document ID | / |
Family ID | 27272394 |
Filed Date | 2003-02-20 |
United States Patent
Application |
20030034299 |
Kind Code |
A1 |
Moghe, Pramod Prabhakar ; et
al. |
February 20, 2003 |
Process for the treatment of industrial effluents using marine
algae to produce potable water
Abstract
The invention relates to a process for the treatment of
industrial effluents using marine algae to produce potable water
which process comprises the steps of: (i) contacting diluted
effluents with marine red algae selected from Porphyra and Liagora,
containing polysaccharides and having sulfate/acetyl functional
group on the cell wall and galactopyranose on their cell membrane,
for a period of at least 30 minutes preferably under stirring; (ii)
treating the effluents from step (i) with calcareous material for a
period of at least 30 minutes, preferably under stirring; (iii)
separating the coagulated material so formed from the supernatant
by conventional methods; and (iv) treating the supernatant with
conventional ion-exchange resins such as cationic ion-exchange
resins, anionic-ion exchange resins and activated charcoal to
produce potable water.
Inventors: |
Moghe, Pramod Prabhakar;
(Pune, IN) ; Panchanadikar, Vinita Vinay; (Pune,
IN) ; Untawale, Arvind Gajanan; (Goa, IN) ;
Dhargalkar, Vinod Kashinath; (Goa, IN) |
Correspondence
Address: |
RANKIN, HILL, PORTER & CLARK, LLP
700 HUNTINGTON BUILDING
925 EUCLID AVENUE, SUITE 700
CLEVELAND
OH
44115-1405
US
|
Assignee: |
COUNCIL OF SCIENTIFIC AND
INDUSTRIAL RESEARCH (AN INDIAN REGISTERED BODY INCORPORATED
UNDER
|
Family ID: |
27272394 |
Appl. No.: |
10/167199 |
Filed: |
June 11, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10167199 |
Jun 11, 2002 |
|
|
|
09482766 |
Jan 13, 2000 |
|
|
|
Current U.S.
Class: |
210/601 |
Current CPC
Class: |
C02F 2103/322 20130101;
C02F 1/42 20130101; C02F 1/001 20130101; C02F 1/283 20130101; C02F
1/5245 20130101; C02F 2103/28 20130101; C02F 3/32 20130101 |
Class at
Publication: |
210/601 |
International
Class: |
C02F 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 10, 1999 |
IN |
1085/DEL/99 |
Aug 10, 1999 |
IN |
1086/DEL/99 |
Claims
What is claimed is:
1. A process for the treatment of diluted effluents from pulp
mills, paper mills or the alcohol manufacturing industry to produce
potable water which process comprises the steps of: (i) contacting
the diluted effluents with a marine red algae selected from the
group consisting of Porphyra and Liagora for a period of at least
30 minutes; (ii) treating the diluted effluents from step (i) with
calcareous material for a period of at least 30 minutes thereby
forming a coagulated material and a supernatant; (iii) separating
the coagulated material from the supernatant of step (ii); (iv)
treating the supernatant of step (iii) with an ion-exchange resin,
filtering to obtain a filtrate of pH 2 to 3; (v) further treating
the filtrate of step (iv) with an ion-exchange resin to obtain a
clear filtrate; and (vi) passing the clear filtrate of step (v)
over a column of activated carbon to produce potable water.
2. The process as claimed in claim 1 wherein the calcareous
material is selected from the group consisting of CaCO.sub.3, lime,
bone powder, shell powder, diatomaceous earth, and salts of
calcium.
3. The process as claimed in claim 1 wherein the ratio of marine
red algae and calcareous material to diluted effluent ranges from
about 0.50 to 2.00 grams per 100 ml of the diluted effluents.
4. The process as claimed in claim 1, wherein the effluents are
diluted about 5 times with water.
5. The process as claimed in claim 1 wherein the effluents are
contacted with marine red algae for a period of about 30 to 120
minutes and treated with calcareous material for a period of about
30 to 120 minutes.
6. The process as claimed in claim 1 wherein the marine red algae
is used in dry powder form.
7. The process as claimed in claim 1 wherein the ion exchange resin
is an anion/cation exchange resin.
8. The process as claimed in claim 1 wherein the separation of the
supernatant from the coagulated material is effected by a method
selected from the group consisting of sedimentation, filtration and
centrifugation.
9. The process as claimed in claim 1 wherein the diluted effluents
contain black liquor effluent waste from paper mills or pulp mills
or spent wash from the liquor manufacturing industry.
10. The process as claimed in claim 1 wherein the diluted effluent
comprises black liquor from a pulp mill or a paper mill having a
chemical oxygen demand of about 15,000 to about 35,000 mg/L and
biological oxygen demand is in the range of about 4000 to about
5000 mg/L
11. The process as claimed in claim 1 wherein the diluted effluent
comprises spent wash produced in the distillery wastes of sugar
factories having a chemical oxygen demand of about 90,000 to about
120,000 mg/L and biological oxygen demand is about 20,000.+-.5,000
mg/L.
12. The process as claimed in claim 1 wherein colorless potable
water is produced.
13. The process as claimed in claim 1 wherein the chemical oxygen
demand of the potable water produced in step (vi) is in the range
of from about 12 to about 88 mg/L.
14. The process as claimed in claim 1 wherein the biological oxygen
demand of the potable water produced in step (vi) is in the range
of from about 20 to about 26 mg/L.
15. The process as claimed in claim 1 wherein the treatment of
diluted effluents is carried out at ambient temperatures.
16. The process as claimed in claim 1 wherein the supernatant from
step (iii) is treated with an ion exchange resin until it attains a
pH range of about 2 to about 3.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation-in-part of application Ser. No.
09/482,766, filed Jan. 13, 2000.
BACKGROUND OF THE INVENTION
[0002] 1. Field of Invention
[0003] The invention relates to an effluent treatment process using
marine algae. More specifically, the invention is concerned with
the separation of organic substances such as lignin and other
coloring matter in aqueous industrial effluents by treatment with
marine algae to produce potable water and sludge containing
unwanted contaminants.
[0004] 2. Description of Related Art
[0005] As is known in the state of art, industrial effluents are
major contaminants in any country. Accordingly, the invention is
directed to a novel method for the treatment of effluents emitted
specifically by pulp and paper mills in the paper industry and in
the production of consumable liquor by the alcohol industry. The
waste produced by the paper industry is basically a black liquor
comprising organic matter, lignin, inorganics and coloring matter.
Similarly, the waste or effluent of the alcohol industry also
contains lignin, phenolic compounds, pigments and other
substances.
[0006] Lignin may be defined as amorphous polyphenolic material
arising from an enzyme mediated dehydrogenative polymerization of
three phenylpropanoid monomers, for example, conyferyl, sinapyl and
p-coumaryl acohols. Lignin (from the Latin lignum, wood), after
cellulose, is the principal constituent of woody structure of
higher plants deposited in xylem cell walls and in part located in
the intercellular spaces. The sulfite waste liquors from paper
mills contain about 3 to 6% lignin, which is not easily
biodegradable. This lignin may act as a source of vanillin,
syringic aldehyde, and can be used as extender for phenolic
plastics as well as to strengthen the rubber, as oil mud additive
to stabilize asphalt, as emulsions to precipitate proteins. Lignin
also can be converted to pure low molecular weight chemicals; it
may serve as an important feedstock for the chemical industry. At
present, only vanillin and dimethyl sulfide are produced
commercially and economically competitive processes for conversion
to phenolic and aromatic chemicals are real possibilities.
[0007] Until the past 2-3 decades or so, large amounts of lignin
were discarded into streams and waterways as dilute aqueous
solutions. This is no longer tolerated, and almost all waste
streams containing lignin are concentrated and burned. In the case
of the paper industry, in order to conform to environmental quality
guidelines, a number of primary and secondary treatment systems to
control effluents are installed. Such treatment comprises use of
clarifiers to remove 85-100wt. % of solids in first treatment and
aerated lagoons or otherwise, and employment of trickling filters,
modified biological systems, charcoal treatment to remove 90-95% of
BOD (Biochemical Oxygen Demand) in secondary treatment by which,
most of the toxicity is removed with very little color.
Ultrafiltrations have also been tried, but have been determined to
be futile in removing total dissolved solids completely.
[0008] Oxygen demand is a significant parameter for determining the
effect of organic pollutants in water. As microorganisms in the
environment ingest the organic material, oxygen is depleted. This
in turn can be harmful to fish and plant life. Wastewater from food
processing is non-toxic but organic. High concentration of
nutrients can be harmful for the environment. Extra quantities of
nitrogen, fat and phosphorus require more oxygen for bacteria to
decompose. If Chemical Oxygen Demand (COD)/Biochemical oxygen
demand (B.O.D) content of the water is excessive, the oxygen supply
in the water may be depleted below the level required to sustain
aquatic life. The Chemical Oxygen Demand (COD) determination is a
measure of the oxygen equivalent of that portion of the organic
matter in a sample that is susceptible to oxidation by a strong
chemical oxidant under controlled conditions. See Standard Methods
for the Examination of Water and Wastewater (APHA, AWWA, WPCF),
Washington, D.C., 20th Ed. (1998).
[0009] The main chemical compounds in wastewater are Chemical
Oxygen Demand (COD), nitrogen, phosphorus, fats, oils and grease.
COD and BOD are important parameters for measurement of organic
matter content and oxygen needed to decompose the organic
compounds. During the decomposition of organic matter there is less
oxygen available in the sea and no oxygen in some places. It is
possible to calculate COD or BOD into standard personal units, 60 g
of oxygen to decompose the organic compounds from one person per
day or equaling of 135 g of oxygen to decompose Chemical Oxygen
Demand (COD) in waste water (COD=2.25.times.BOD). Monitoring of COD
is important for design and operation of wastewater treatment
equipment.
[0010] a. Paper Industry:
[0011] The pulp and paper industry uses large amounts of water,
which is recycled and reused resulting in temperature rise and
dissolution of more solids in water. But this causes problems such
as e.g. corrosion, slime and other deposits. Directly or indirectly
all of these (i.e. BOD, color and toxicity) affect aquatic
life.
[0012] Total dissolved solids are removed and used as energy source
in fuel. Biomethanation has also been attempted. All these do not
meet the standards of pollution control. Therefore it becomes very
essential to remove color, total dissolved solids with negligible
quantity of BOD and COD.
[0013] In the prior art, following methods are used for the
separation of lignin from black waste liquid in paper industry:
[0014] (i) Purification of waste waters for installation of
bleaching sulfate paper, Udeleholms A. B. Fr. Demande 2, 202,043
May 3, 1974. Swed Appl. 12772/72 October 4 CA 82: 34833 g
(1975):
[0015] Lignin and other organic matter are mostly precipitated from
wastewater by addition of mineral acid and by filtration. The
filtered wastewater is treated with feebly alkaline ion exchange
resin activated with acid. The resin is then eluted with alkali to
remove adsorbed lignin. The elute together with solution of
original precipitate in alkali are recycled to the sulfate pulp
process, preferably by burning in the black liquor recovery
process. In this process the ion exchange resins used are
commercially available chemical components.
[0016] (ii) Desulfurisation of waste gas with pulp waste liquor,
Suyama A; Hayashi, H (Mitsubishi Kausha Ltd. Toyo Tokushi Kogyo K.
K.) Jap. Kokai 76,20,089 Feb. 17, 1976. CA 85: 67527a 9(1976):
[0017] Fiber free black liquor is used for waste gas
desulfurisation and lignin in waste liquor is precipitated as
lignin sulfate. The fiber is removed by boiling. Thus 1100 ppm
SO.sub.2 containing diesel oil boiler flue gas was desulfurised
with boiled black liquor (pH 12) to 93%. The spent liquor was air
oxidized and the coagulant was added to precipitate lignin and
other substances.
[0018] (iii) Recovery of sodium hydroxide and black liquor from
cellulose manufacture, Torras hostench S. A. Belg. 861, 585 Mar.
31, 1977. Span Appl. 461, 364 Aug. 4, 1977. CA 89: 61292
(1978):
[0019] An improved process for title recovery as compared to
Spanish patent No. 29,158 comprises carbonation of spent liquor
(preconcentrated to 40% from 10-15%) by treatment of pulp by
bubbling CO.sub.2 through a stream of spent liquor in a counter
current system from bottom to the top of the liquor at
75-85.degree. C. and 0.5 kg/cm.sup.2 and treating the resulting
silica-lignin precipitate with 0.03 N NaOH to redissolve the lignin
for recycling to carbonated black liquor before further
concentrating by evaporating.
[0020] (iv) Recovery of inorganic compounds from Kraft pulping
black liquors, Domtar Inc. Jpn. Kokai Tokkyo Koho 58 36292 (83
36292) Mar. 3, 1985. Appl. 382387 Jul. 23, 1981. CA 99: 89814 h
(1983):
[0021] Sodium compound from Kraft pulping black liquors are
recovered by first acidifying the cool liquor with acids containing
H.sub.2SO.sub.4 to Kraft black liquor by ultracentrifugation (UC)
of liquor, followed by electrodialysis (E) of UC permeate treating
deionate from E with acid to precipitate lignin and electrolytic
H.sub.2O splitting of resulting solution.
[0022] (v) Removal of lignin alkaline waste pulping liquors,
Ishikawa H.; Kade K. (Oji Paper Co. Ltd.). Jpn. Kokai Tokkyo JP 62
90398 (87 90 389) Apr. 24, 1987 85 226 870 October 1985. CA 107: 79
808 d (1987):
[0023] The title removal involved colloidising the solution lignin
followed by ultrafiltration. Thus beech chips were cooked at
effective alkali 14% sulfidity 25% liquor ratio 4 and 165. The
resulting black liquor was filtered, adjusted to pH 11, 10 and 9
with CO.sub.2 and ultra filtered to give delignification of 89%,
94% and 97% respectively.
[0024] (vi) Manufacture of methylolated lignin from black Kraft
liquor residues, Dilling Peter (West Vaco Corp.) U.S. Pat. No.
4,764,597 Aug. 16, 1988 Appl. 61 460 Jun. 15, 1987 CA 109: 212612 v
(1988):
[0025] Methylolated lignin is manufactured from black Kraft liquor
residues by initially oxidizing black Kraft liquor containing
lignin and salt in situ methylolation of lignin with an aldehyde
followed by lowering the pH of the black Kraft liquor residue to
precipitate methylolated lignin and finally recovering the
precipitated methylolated lignin from black liquor residue. Thus a
black Kraft residue (pH 13) was oxidized with air until the
Na.sub.2S content was 1% and then stirred with 3 lb/mole HCHO/1000
lb lignin at 70 for 2 h. The black liquor containing methylolated
lignin was acidified with H.sub.2SO.sub.4 to a pH of 4. The
methylolated lignin was coagulated at 85, filtered, washed with
water. The methylolated slurry was then treated with
triethanolamine to a pH of 7 and then sufonated with SO.sub.2 at
205.degree. F. for 12 h to give sulfomethylolated, I amine salt
useful as dispersant for azodyes.
[0026] (vii) Recovery of solids from black liquors, Caperos, S. A.
Span ES 2, 006, 964 May 16, 1989 Appl. 8, 801,697 May 27, 1988. CA
114: 26042 n (1991):
[0027] Solids in black liquors are recovered, as precipitate by
mixing 1 part black liquor with 0.1-1.0 parts reactive
precipitating agents and separating the precipitate. The 1000
cm.sup.2 black liquor E globules were mixed with 1000 cm.sup.2
saturated solution of CaCl.sub.2 in EtOH to form precipitate which
was separated by centrifugation and washed with 1:1 EtOH water to
give precipitate 134 g, organic components, 105 g lignin, 53 g and
pentosans 8 g with 85% yield.
[0028] (viii) Areding process of paper black liquor with
sulfur-dioxide, Sun, L; Xu, Mu, H et al (Chinese Academy of
Sciences, environment-estimating department). Faming Zhuangli
Shenging Ganakai Shouming Shu. CA 1,050 064 Mar. 20, 1991 Appl. 89
106 694 Sep. 4, 1989 CA 115: 282382 t (1991):
[0029] The title process is described by heating black liquor with
SO.sub.2 to separate lignin and recover Na sulfite from the
remaining acidic solution.
[0030] (ix) Treatment of black pulp liquor by conservation and
precipitation, Zhang M; F Z; Shenging G; Shouming S. CA 1, 057 079.
Dec. 18, 1991 Appl. 90, 104, 181 Jun. 5, 1990 CA 117: 173 646 c
(1992):
[0031] Black pulping liquor is treated by adding solid CaCl.sub.2
or an aqueous solution containing CaCl.sub.2 (2-5 g/100 ml) to
black pulping liquor, coagulating and precipitating to remove
lignin and recovering diluted NaOH solution. Thus 17.5 g lignin and
6 g/L NaOH aqueous solution were recovered by adding 3 g CaCl.sub.2
in 100 ml sulfate black liquor (from preparing of pine pulp),
precipitating and filtration.
[0032] In hitherto known processes main drawbacks are as
follows:
[0033] 1. The use of acidic media involves problems of
corrosion.
[0034] 2. Use of alkaline media causes further filtration problems
due to colloidal particles. These processes result in incomplete
removal of organics as well as inorganic matter from the effluent
resulting into colored effluent water, due to organics such as
lignin and mellanoidin.
[0035] b. Alcohol Industry:
[0036] The alcohol industry (i.e., the production of consumable
liquors containing ethyl alcohol) in India uses molasses as the
principal raw material. The alcohol recovery ranges from 7 to 9%
from the molasses. Fermentable sugars, organic and inorganic
chemicals in the molasses find their way into effluents, which
causes high BOD/COD. This effluent, known as "spent wash", is also
acidic in nature, forms hydrogen sulfide, emanating bad odor having
black color and hence cannot be disposed as such into the water
stream. In the spent wash, origin of black color is due to plant
pigment melanoidins, polyphenolic compounds, caramels, which are
produced by thermal degradation and condensation reaction of sugar.
Spent wash contains lignin and colouring material.
[0037] In the prior art, following methods are used for the
separation of coloring bodies from spent wash in alcohol
industries:
[0038] This is mainly useful to minimize industrial pollution due
to the spent wash.
[0039] (i) Apparatus for the decolorizing molasses, Chida, T,
Tsuboi, H. Jpn. Kokai. 77, 90, 639, Jul. 30, 1977, pp.3, CA 88:
24490c. (1978):
[0040] Molasses was decolorized with active carbon in an adsorption
tower containing plate electrodes impressed with d. c. voltage. The
pigments were di-electric, polarized by electrodes and adsorbed by
active carbon. Thus molasses was decolorized 98% in an adsorption
tower containing granular active carbon and vertical carbon
electrodes at 10 cm intervals at 0.1 A/dm.sup.2 and 8V with
retention time 3 h.
[0041] (ii) Purification of molasses, Kaga T, Hiramoto, T;
Hamanaka, K; Sato, M. & Tokida Y. Jpn. Kokai 77, 108, 035. Sep.
10, 1977, pp.7,. CA 88: 75566q. (1978):
[0042] Granular active carbon was used to decolorize brown liquors
of Brix 62-3 and stammer color 5.2-5.4 was passed through a
regenerated active column at 75-8.degree. C. and solids carbon
ratio 100 with 64% decolourization and molasses having Brix 35-6 pH
5.8 & stammer color 70 was passed through the same column at
72-3.degree. C.
[0043] (iii) Removal of coloring substances from molasses
solutions, Shvets V N; Knogotkova F I; Pavyuchenko L N. Izv. Vyssh
Uchebn. Zewed Pisheh. Technol. 1977, (4) 31-5, 88: 8827n.
(1978):
[0044] The filtration of molasses diluted to 35% with water through
a column filled with AV-16GS. (12626-33-4) anion exchanger in
chloride form, removed >50% of colored substances and organic
impurities. The effectiveness of removal of these substances
decrease in order invert sugar>melanoidins>caramels. The
decrease in the concentration of molasses improved its
decolourization by exchanger. Colored substances in molasses could
be coagulated by d. c. and removed by filtration but the procedure
was effective only below 50% molasses conc., colored substances in
molasses are not adsorbed by Soviet AGS-4 activated carbon.
[0045] (iv) Sorption of sugar coloring substances on ion
exchangers, Wyroba A. Zesz. Nauk. Univ-Jagiellon Pr.Chem. 1976, 21,
355-61. CA 88: 8826 m.(1978):
[0046] The decoloring power of ion exchange resin towards molasses
(A) sugar from 3rd crystal (B), thick syrup (C) and clear syrup (D)
is not the same. Thus centranol W-291 (I) (51258-00-5) and
Amberlite IRA-900 (9050-97-9) reduce best the color of A & B or
Amberlite IRA-68 II (9056-59-1) can be used for decolouring C &
D is best decolorized by II, although Amberlite IRA-4015
(9036-93-S) can also be used. A and C can be efficiently
decolorized with carboraffina activated carbon.
[0047] (v) Methods for improved determination of sugar content in
dark colored products of sugar industry, Zagorulko A. Ya.; Boiko E.
S.; Korobeinikova L. A.; Ponomarenko A.; Burlyai T. F. Sakh Prom-St
1978 (1) 65-6. CA 88:91344w. (1979):
[0048] Colored substances present in the intermediate of sugar
manufacture and molasses can be removed by combined treatment first
with Pb(OAC) 4 (546-67-8) and then with activated carbon. The
decolorized solutions are made up to known volumes and used for the
polarimetric/polometric of sucrose (I) (57-50-1). Activated carbon
does not absorb (I) (87-50-1) and it does not require washing after
it is filtered off.
[0049] (vi) Waste water treatment, Sakurai, S. Jpn. Kokai Tokyo
Koho. 79 51,250. Apr. 21, 1979. CA 91: 78574p. (1979):
[0050] Hydrogen peroxide solution is added to waste water, then the
pH is adjusted to <4 and waste water electrolyzed with an Fe
anode to oxidize soluble pollutants. Adjusting the pH in the range
of 6.0-8.5 flocculates the insoluble pollutants.
[0051] In hitherto known processes, main drawbacks are the use of
acidic media, which involves problems of corrosion, filtration due
to colloidal particles and incomplete removal of organics as well
as inorganic matter in effluent water and colored effluent water
due to presence of organic matter mainly lignin and
mellanoidin.
[0052] c. Sewage Treatment
[0053] Many studies have been conducted on the use of red marine
algae such as Porphyra and Liagora for the treatment of effluents.
The following references will be useful to assess the use of red
algae in general and Porphyra & Liagora in sewage disposal
plants:
[0054] (i) Effect of effluent from sewage disposal plant of the
growth of Porphyra, Ohgai, M.; Sugimoto, T.; Murase, N.; Suisan, Z.
1994 42(1), 41-6,CA 121: 153004w. (1994):
[0055] A laboratory culture study was made to examine the effect of
effluent for sewage disposal plant on the growth of Porphyra and 4
species of diatoms. The culture media are prepared for different
concentrations of effluents. The growth of conchospores and thalli
of Porphyra was slightly accelerated by the addition of effluent at
a concentration of about 0.3-10.0%. Similar growth trend was
observed in species of diatoms. Growth was suppressed at 30.0%
effluent concentration.
[0056] (ii) Toxicity bio-assay of the municipal sewage effluents
using seaweed Toshiro, M.; Akio, M.; Kankyo, M. 1993 16(5), 327-38,
CA 119: 209657q. (1993):
[0057] Bioassay techniques for testing treated wastewater and toxic
chemicals in seawater by monitoring seaweed growth are discussed.
Strongest toxic substances for growth of Porphyra were
monochloramines resulting from chlorinated sewage.
[0058] (iii) Studies on the effects of municipal waste water on the
growth of Porphyra, Toshiro, M.; Kazuo, O.; Akio, A.; Tomao, Y.;
Suisun, N.; 1988 54(10) CA 110: 34929q. 191989):
[0059] Four kinds of chlorinated solutions were investigated to
identify the causative substance inhibiting the growth of Porphyra
yezoensis thalli. Inhibitory effects were measured in terms of
length and number of dead cells. Tests were conducted using
cultures dosed with chlorinated municipal sewage effluent after
nitrification and chlorinated ion exchange water respectively.
Chloramine and chlorinated ion exchanged water was considered to be
the causative substance in the growth inhibition of Porphyra.
[0060] (iv) Utilization of nitrogen and phosphorus from treated
sewage and bay sediment by marine algae, Nobuyoshi, I.; Kunio, K.;
Yuji, O.; Takashi, N.; Zasshi, G.; 1987 42(1/2) CA 108; 173165j.
(1988):
[0061] Porphyra yzoensis preferred NH.sub.4--N to NO.sub.3--N in
the growth medium. But growth was affected when NH.sub.4--N level
became >8 and 12 mg/L resulting in rapid decrease of cell number
and death of almost all cells at 32 mg/L after 4 days.
[0062] (v) The bioaccumulation of metals by Rhodophyta sp., Malea,
P.; Haritonidis, S.; Stratis, I. 1994 37(6), 505-13, CA 122:
169365w.9 (1995):
[0063] The bioaccumulation of Fe, Cu, Zn, Cd, Pb, Na, K, Ca and Mg
by seven species of red algae (Rhodophyta) were studied after their
seasonal collections from 9 stations in Antikgra Gulf. This area is
characterized by its bauite substrate and discharge of waste from
an aluminum factory. No metal in Liagora showed a significant
correlation with the concentration of the dissolved metals in
seawater.
[0064] (vi) Polysaccharide of algae 43 neutral xylan and sulfated
xylomannan from red seaweed, Usor, A. I.; Dobkina, I. M.; 1991
17(8) CA 115: 275755p. (1992):
[0065] Sulfated xylomannan and several fractions of neutral
polysaccharides have been isolated from red alga Liagora.
Water-soluble neutral xylan purified through copper complex was
shown to be a linear polymer having .beta.-1-4 and B-1-3 linkages
between D-xylopyranose residues at a ratio of 6:1. Ion sulfated
polysaccharide was investigated using partial hydrolysis,
methylation after and before desulfation as 13C NMR
spectroscopy.
[0066] (vii) Polysaccharide of algae, Usov, A. I.; Dobkina, I. M.
1988 14(5), CA 109 :70387z. (1989):
[0067] A sulfated xylomannan and several fractions of neutral
polysaccharides were isolated from red seaweed Liagora. Xylomannan
was shown to contain D-mannose and D-xylose of sulfate and has a
linear backbone of alpha-1-3 linked d-mannopyranose residues. On
the average there are two branching points and seven sulfate groups
attached to position 6 & 2 at a ratio of about 2:1 at every 14
mannopyranose residues of the main chain.
[0068] (viii) Chemical study of Cuban seaweed, Estevez, M. L.;
Olivan, D. L; Velazquez, R. 1985 1(1), 87-93, CA 104: 165402m,
(1986):
[0069] Polysaccharides were examined from 13 species of red algae
collected on Cuban coast and soluble sulfated polysaccharides were
found in predominant amounts. Polysaccharides are primarily
composed of galactose. These alga form a firm carrageenan gel when
polysaccharide yield of >30% of dry weight were attained from
alga.
[0070] There is continued interest on development of new improved
processes for separation of lignin, organic matters, and inorganic
compounds from spent wash produced in the distillery wastes of the
alcohol industry and black liquor products from pulp and paper
mills in the paper industry. It is a known fact that
lignin-containing effluents are not degradable and hence cause
disposal problems in the environment.
OBJECTS OF THE INVENTION
[0071] The main object of the present invention is to provide a
process for the treatment of effluents from the alcohol and paper
industry to produce potable water using marine red algae. Yet
another object is to treat the effluents in a manner so as conform
with environmental rules and standards. Yet another object is to
provide a process for the treatment of industrial effluents to
produce potable water using red algae essentially having
polysaccharide with sulfate or acetyl group on cell wall and
galactopyranose residues on cell membrane.
BRIEF SUMMARY OF THE INVENTION
[0072] The invention provides a process for the treatment of
industrial effluents to produce potable water, using marine algae.
Specifically, the invention concerns the separation of organic
substances such as lignin and other colouring matter from
industrial effluents by treatment of the effluents with marine
algae such as Porphyra and Liagora.
[0073] Seaweeds are the source of gel forming polysaccharides
(phycocolloides) and widely used in industry as emulsifying agents,
gelling agents, stabilizers, thickeners and suspension agents. The
chemical structure of Liagora reveals the presence of a sulfated
xylomannan and several fractions of neutral polysaccharides and
other charged groups like mannans and xylans having phycocolloid
properties and are anionic in nature. Polyelectrolytes with marked
cation exchange properties are significant in plants living in
saline medium. Further at pH>3 sulfated polysaccharide,
xylomannan, several fractions of neutral polysaccharides like
D-xylopyranose, D-mannose and D-mannopyranose are responsible for
the selective adsorption of coloring chromophores and potassium
with the adsorption of the lignin polyphenolic bodies. In
accordance with the invention, the obtained pale yellow effluent
can be treated with calcarious material particularly lime powder
CaO>98%, ion exchange system and activated carbon to remove
organics, inorganics and trace of coloring matter to colorless
water which can be recycled in the process in a period ranging up
to 4-6 hours.
[0074] In the process of the present invention, lignin, phenolic
compounds, pigments and other substances and sugars are separated
by treating the spent wash with sea weeds e.g. Porphyra, Liagora
and calcareous material preferably lime powder. The applicants,
during their study on marine algae, found that in the presence of
Porphyra, chemical structure 1,3 linked .beta.-D-galactopyranose
and 1,4-linked 3,6-anhydrous alpha-L-galactopyranose and other
charged groups like mannans and xylans have better phycocolloid
properties and are anionic polyelectrolytes with marked cation
exchange properties are of significance in plants living in saline
medium. After carefully going through the literature, it is noticed
that use of seaweed polysaccharide of Porphyra as a decolorizing
agent is not mentioned.
[0075] The combination of Porphyra and lime powder was found to
remove organics, inorganics and the removal of the color of spent
wash from black to pale yellow, which was further treated with
active carbon to get almost colorless liquid. The treated effluent
was found to be passing BOD, COD and all the other parameters of
effluent treated water required by the environmental agencies. All
the operations in this process are done at room temperature, hence
saves energy costs, the treated water can be recycled to the
process. The resins used in the process can be generated with known
methods.
[0076] The foregoing and other features of the invention are
hereinafter more fully described and particularly pointed out in
the claims, the following description setting forth in detail
certain illustrative embodiments of the invention, these being
indicative, however, of but a few of the various ways in which the
principles of the present invention may be employed.
DETAILED DESCRIPTION OF THE INVENTION
[0077] Accordingly, the present invention provides an improved
process for the treatment of diluted effluents containing lignin
from pulp mills, paper mills or the liquor manufacturing industry
to produce potable water which process comprises the steps of:
[0078] (i) contacting the diluted effluents with a marine red algae
selected from the group consisting of Porphyra and Liagora, the
marine red algae containing polysaccharides and having
sulfate/acetyl functional groups on their cell walls and
galactopyranose in their cell membrane, for a period of at least 30
minutes;
[0079] (ii) treating the diluted effluents from step (i) with
calcareous material for a period of at least 30 minutes thereby
forming a coagulated material and a supernatant;
[0080] (iii) separating the coagulated material from the
supernatant from step (ii);
[0081] (iv) treating the supernatant from step (iii) with an
ion-exchange resin and filtering the treated supernatant to obtain
a filtrate; and
[0082] (v) passing the filtrate from step (iv) over a column of
activated carbon to produce potable water.
[0083] In another embodiment, the effluents may be diluted about 5
times with water selected from tap water, mineral water, natural
water, distilled water, demineralized water. In still another
embodiment, the effluents are contacted with marine algae for a
period of about 30-120 minutes, and treatment with calcareous
material may be effected for 30-120 minutes. In still another
embodiment the calcareous material is selected from CaCO.sub.3,
lime, bone powder, shell powder, diatomaceous earth, salts of
calcium and natural sources thereof. In another aspect, the ratio
of marine red algae and calcareous material to diluted effluent
preferably ranges from 0.50 to 2.00 g per 100 ml. Yet another
aspect is that the said algae used may be in the form of dried
powder or embedded in neutral matrix or in natural form. In another
embodiment the ion exchange resin is selected from anion/cation
exchanger resins such as commercially available IR-120, IR-400 and
IRC-50.
[0084] In a feature of the present invention, the conventional
methods used to separate the coagulated impurities may be
sedimentation, filtration or centrifugation. In another feature of
the present invention, the treated effluent was found to be meeting
all standards of the Pollution Control Act such as COD/BOD levels,
total dissolved solids & color. The final water produced at the
end of the process is colorless. In yet another feature, all
operations of the process are effected at room temperature without
the use of mineral acid to render the effluents substantially free
of organic and inorganic matter and the treated water can be
recycled to the process or let the natural resource. The resin used
in the process can be regenerated by conventional methods.
[0085] In a preferred embodiment of the invention, the amount of
Porphyra and Liagora used is within the range of from about 0.15%
and about 2.00%, and more preferably in the range between about
0.25% and about 1.0%, based upon the total weight of the effluent
being treated. In a preferred embodiment of the invention, the
amount of calcareous material used is within the range between
about 0.15% and about 2.00%, and more preferably in the range
between about 0.25% and about 1.0%, based upon the total weight of
the effluent being treated. In another preferred embodiment of the
invention, the effluent is diluted with water prior to treatment
such that an effluent to water diluent ratio is maintained within
the range of from about 1:1 to about 1:5, and more preferably
within the range of from about 1:3 to 1:5.
[0086] Generally speaking, the effluent water generated by the
alcohol industry has a COD level in the range of about 90,000 to
about 120,000 mg/L (ppm) and a BOD level in the range of about
20,000.+-.5,000 ppm. The effluent water from the paper industry has
a COD level in the range of about 15,000 to about 35,000 mg/L (ppm)
and a BOD level of about 4,000 to 5,000 ppm. Thus, the present
invention provides a method of treating effluent water having an
initial Chemical Oxygen Demand in the range of about 15,000 to
about 120,000 ppm and an initial Biological Oxygen Demand in the
range of about 4,000 to about 20,000 ppm.
[0087] Effluents from the paper industry characteristically include
soluble lignin salts of polyphenolic bodies, for example,
coniferyl, sinapyl and p-coumaryl, typically from about 3% to about
6% by weight, alcohols, and pigments, such as melanoidins.
Effluents from the alcohol industry characteristically include
fermentable sugars, plant pigments, lignin, caramels, reducing
sugars, sulphated ash, carbonated ash, dry matter and oxides of
magnesium, potassium, phosphorous, aluminium, iron and sulphites
and bisulphites of sodium, potassium.
[0088] Preferably, the reduction from initial BOD (i.e., prior to
treatment) to final BOD (i.e., after treatment) is in the range of
from about 97.35% to about 99.99%, and more preferably from about
98.5% to about 99.9%. Preferably, the reduction from initial COD
(i.e., prior to treatment) to final COD (i.e., after treatment) is
in the range of from about 94.0% to about 99.99%, and more
preferably in the range of from about 95.0% to about 99.85%.
Preferably, the final BOD and COD of treated water is within the
range of from about 15 to about 35 mg/L and from about 10 to about
100 mg/L, respectively, and more preferably is within the range of
from about 20 to about 26 mg/L and from about 12 to about 88 mg/L,
respectively.
[0089] In the preferred embodiment of the invention, the diluted
effluent is contacted with Porphyra or Ligora under stirring for a
period ranging from about 30 minutes to about 5 hours, and more
preferably for a period of from about 30 minutes to about 2 hours.
Treatment with Indion resin and further treatment with IR-400 resin
is carried out continuously by passing effluent through columns
containing such ion-exchange resins. In the preferred embodiment of
the invention, the ion-exchange resin or resins used are selected
from anionic and cationic ion-exchange resins belonging to Indion
type ino-exchange resins.
[0090] The invention is described hereinafter, with reference to
the following examples, which are illustrative only and should not
be construed to the limit of the scope of present invention.
EXAMPLE 1
[0091] 20 ml of black liquor from the paper industry was diluted to
100 ml with water and then contacted with Porphyra dried powder 1
g, under stirring for 2 hours followed by addition of lime powder
1.0 g. The sludge was separated by filtration and the filtrate was
treated with Indion resin (20 ml) at a pH of about 2-3. The
filtrate was again passed through a column of IR-400 resin. The
elute was passed over column of activated carbon (5 g) to obtain
colorless water with no organic matter. Color reduction was 92%.
The initial COD of black liquor was 7712.64 mg/L and after Porphyra
and lime treatment was brought down 1021.76 mg/L, and further to 12
mg/L with ion exchange system. The BOD of colorless water obtained
was 26.
EXAMPLE 2
[0092] 20 ml of black liquor from the paper industry was diluted to
100 ml with water and then contacted with Porphyra dried powder 0.5
g, under stirring for 2 hours followed by addition of lime powder
0.5 g. The sludge was separated by filtration and the filtrate was
treated with indion resin (20 ml) to bring its pH to 2-3. The
filtrate was again passed through a column of IR-400 resin. The
elute was passed over column of activated carbon (5 g) to obtain
colorless water with no organic matter. Color reduction was 94%.
The initial COD of black liquor was 7712.64 mg/L and after Porphyra
and lime treatment was brought down to 1326.40 mg/L and further to
60 mg/L with ion exchange system. The BOD of the colorless water
obtained was 20.
EXAMPLE 3
[0093] 20 ml of black liquor from the paper industry was diluted to
100 ml with water and then contacted with Porphyra dried powder
0.25 g under stirring for 2 hours followed by addition of lime
powder 0.25 g. The sludge was separated by filtration and the
filtrate was treated with Indion resin (20) ml to bring its pH to
2-3. The filtrate was again passed through a column of IR-400
resin. The elute was passed over column of activated carbon (5 g)
to obtain colorless water with no organic matter. Color reduction
was 93%. The initial COD of black liquor was 7721.64 mg/L and after
Porphyra and lime treatment was brought down to 2229.89 mg/L and
further to 88 mg/L with ion exchange system. The BOD of the
colorless water obtained was 22.
EXAMPLE 4
[0094] 20 ml of black liquor from the paper industry was diluted to
100 ml with water and then contacted with Liagora dried powder 1 g
under stirring for 2 hours followed by addition of lime powder 1.0
g. The sludge was separated by filtration and the filtrate was
treated with Indion resin (20 ml) to bring its pH to 2-3. The
filtrate was again passed through a column of IR-400 resin. The
elute was passed over column of activated carbon (5 g) to obtain
colorless water with no organic matter. Color reduction was 86%.
The initial COD of black liquor was 7712.64 mg/L and after Liagora
and lime treatment was brought down to 995.4 mg/L and further to 12
mg/L with ion exchange system. The BOD of the colorless water
obtained was 26.
EXAMPLE 5
[0095] 20 ml of black liquor from the paper industry was diluted to
100 ml with water and then contacted with Liagora dried powder 0.5
g under stirring for 2 hours followed by addition of lime powder
0.5 g. The sludge was separated by filtration and the filtrate was
treated with Indion resin (20 ml) to bring its pH to 2-3. The
filtrate was again passed through a column of IR-400 resin. The
elute was passed over column of activated carbon (5 g) to obtain
colorless water with no organic matter. Color reduction was 94%.
The initial COD of black liquor was 7712.64 mg/L and after Liagora
and Lime treatment was brought down to 1033.4 mg/L and further to
60 mg/L with ion exchange system. The BOD of the colorless water
obtained was 20.
EXAMPLE 6
[0096] 20 ml of black liquor from the paper industry was diluted to
100 ml with water and then contacted with Liagora dried powder 0.25
g under stirring for 2 hours followed by addition of lime powder
0.25 g. The sludge was separated by filtration and the filtrate was
treated with Indion resin (20 ml) to bring its pH to 2-3. The
filtrate was again passed through a column of IR-400 resin. The
elute was passed over column of activated carbon (5 g) to obtain
colorless water with no organic matter. Color reduction was 97%.
The initial COD of spent wash was 7712.64 mg/L and after Liagora
and lime treatment was brought down to 2021.76 mg/L and further to
88 mg/L with ion exchange system. The BOD of the colorless water
obtained was 22.
EXAMPLE 7
[0097] 20 ml of spent wash from the alcohol industry was diluted to
100 ml with water and then contacted with Porphyra dried powder 1 g
under stirring for 2 hours followed by addition of lime powder 1.0
g. The sludge was separated by filtration and the filtrate was
treated with Indion resin (20 ml) to bring its pH to 2-3. The
filtrate was again passed through a column of IR-400 resin. The
elute was passed over column of activated carbon (5 g) to obtain
colorless water with no organic matter. Color reduction was 89%.
The initial COD of spent wash was 58032.00 mg/L and after Porphyra
and Lime treatment was brought down 4567.68 mg/L and further to 12
mg/L with ion exchange system. The BOD of the colorless water
obtained was 26.
EXAMPLE 8
[0098] 20 ml of spent wash from the alcohol industry was diluted to
100 ml with water and then contacted with Porphyra dried powder 0.5
g under stirring for 2 hours followed by addition of lime powder
0.5 g. The sludge was separated by filtration and the filtrate was
treated with Indion resin 20 ml to bring its pH to 2-3. The
filtrate was again passed through a column of IR-400 resin. The
elute was passed over column of activated carbon (5 g) to obtain
colorless water with no organic matter. Color reduction was 86%.
The initial COD of spent wash was 58032.00 mg/L and after Porphyra
and Lime treatment was brought down to 3706.56 mg/L and further to
60 mg/L with ion exchange system. The BOD of the colorless water
obtained was 20.
EXAMPLE 9
[0099] 20 ml of spent wash from the alcohol industry was diluted to
100 ml with water and then contacted with Porphyra dried powder
0.25 g under stirring for 2 hours followed by addition of lime
powder 0.25 g. The sludge was separated by filtration and the
filtrate was treated with Indion resin (20 ml) to bring its pH to
2-3. The filtrate was again passed through a column of IR-400
resin. The elute was passed over column of activated carbon (5 g)
to obtain colorless water with no organic matter. Color reduction
was 98%. The initial COD of spent wash was 58032.00 mg/L and after
Porphyra and Oyster treatment was brought down to 3600.29 mg/L and
further to 88 mg/L with ion exchange system. The BOD of the
colorless water obtained was 22.
EXAMPLE 10
[0100] 20 ml of spent wash from the alcohol industry was diluted to
100 ml with water and then contacted with Liagora dried powder 1 g
under stirring for 2 hours followed by addition of lime powder 1.0
g. The sludge was separated by filtration and the filtrate was
treated with Indion resin (20 ml) to bring its pH to 2-3. The
filtrate was again passed through a column of IR-400 resin. The
elute was passed over column of activated carbon (5 g) to obtain
colorless water with no organic matter. Color reduction was 97%.
The initial COD of spent wash was 58032.00 mg/L and after Liagora
and Oyster treatment was brought down to 1235.52 mg/L and further
to 12 mg/L with ion exchange system. The BOD of the colorless water
obtained was 26.
EXAMPLE 11
[0101] 20 ml of spent wash from the alcohol industry was diluted to
100 ml with water and then contacted with Liagora dried powder 0.5
g under stirring for 2 hours followed by addition of lime powder
0.5 g. The sludge was separated by filtration and the filtrate was
treated with Indion resin (20 ml) to bring its pH to 2-3. The
filtrate was again passed through a column of IR-400 resin. The
elute was passed over column of activated carbon (5 g) to obtain
colorless water with no organic matter. Color reduction was 94%.
The initial COD of spent wash was 58032.00 mg/L and after Liagora
and Lime treatment was brought down to 1834.56 mg/L and further to
60 mg/L with ion exchange system. The BOD of the colorless water
obtained was 20.
EXAMPLE 12
[0102] 20 ml of spent wash from the alcohol industry was diluted to
100 ml with water and then contacted with Liagora dried powder 0.25
g under stirring for 2 hours followed by addition of lime powder
0.25 g. The sludge was separated by filtration and the filtrate was
treated with Indion resin (20 ml) to bring its pH to 2-3. The
filtrate was again passed through a column of IR-400 resin. The
elute was passed over a column of activated carbon (5 g) to obtain
colorless water with no organic matter. Color reduction was 88%.
The initial COD of spent wash was 58032.00 mg/L and after Liagora
and lime treatment was brought down to 2000.07 mg/L and further to
88 mg/L with ion exchange system. The BOD of the colorless water
obtained was 22.
[0103] The experimental conditions and results from Examples 1-6
and 7-12 above are set forth in Tables 1 and 2, respectively,
below:
1 TABLE 1 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Effluent 20 ml 20 ml
20 ml 20 ml 20 ml 20 ml After Dilution 100 ml 100 ml 100 ml 100 ml
100 ml 100 ml Porphyra 1 g 0.5 g 0.25 g -- -- -- Liagora -- -- -- 1
g 0.5 g 0.25 g Lime 1 g 0.5 g 0.25 g 1 g 0.5 g 0.25 g Indion resin
20 ml 20 ml 20 ml 20 ml 20 ml 20 ml Color Reduction 92% 94% 93% 86%
94% 97% Initial COD (mg/L) 7,712.64 7,712.64 7,712.64 7,712.64
7,712.64 7,712.64 COD after 1st step 1,021.76 1,326.4 2,229.89
995.4 1,033.4 2,021.76 Final COD 12 60 88 12 60 88 COD Reduction
95.0% to 99.0% Initial BOD (ppm) 5,000 5,000 5,000 5,000 5,000
5,000 Final BOD 26 20 22 26 20 22 BOD Reduction 99.4% to 99.6%
[0104]
2 TABLE 2 Ex. 7 Ex. 8 Ex. 9 Ex. 10 Ex. 11 Ex. 12 Effluent 20 ml 20
ml 20 ml 20 ml 20 ml 20 ml After Dilution 100 ml 100 ml 100 ml 100
ml 100 ml 100 ml Porphyra 1 g 0.5 g 0.25 g -- -- -- Liagora -- --
-- 1 g 0.5 g 0.25 g Lime 1 g 0.5 g 0.25 g 1 g 0.5 g 0.25 g Indion
resin 20 ml 20 ml 20 ml 20 ml 20 ml 20 ml Color Reduction 89% 86%
98% 86% 94% 97% Initial COD (mg/L) 58,032.0 58,032.0 58,032.0
58,032.0 58,032.0 58,032.0 COD after 1st step 4,567.68 3,706.56
3,600.29 1,235.52 1,834.56 2,000.7 Final COD 12 60 88 12 60 88 COD
Reduction 95.62% to 99.75% Initial BOD (ppm) 5,000 5,000 5,000
5,000 5,000 5,000 Final BOD 26 20 22 26 20 22 BOD Reduction 99.4%
to 99.6%
EXAMPLE 13
[0105] Six 20 ml aliquots of black liquor from the paper industry
were diluted with fresh water in the effluent to water ratios shown
in Table 3 below. The aliquots were then contacted with Liagora
dried powder under stirring for 2 hours followed by addition of
lime powder. The sludge was separated by filtration and the
filtrate was treated with Indion resin (20 ml) to bring its pH to
2-3. The filtrate was again passed through a column of IR-400 resin
and then passed over a column of activated carbon (5 g). The
percentage color reduction was recorded, and reported in Table 3
below:
3TABLE 3 Sample No. Effluent to Water Percent Color Reduction 13a
1:0 0% 13b 1:1 8% 13c 1:2 17% 13d 1:3 56% 13e 1:4 69% 13f 1:5
96%
EXAMPLE 14
[0106] Six 20 ml aliquots of spent wash from the alcohol industry
were diluted with fresh water in the effluent to water ratios shown
in Table 3 below. The aliquots were then contacted with Liagora
dried powder under stirring for 2 hours followed by addition of
lime powder as per example 13. The sludge was separated by
filtration and the filtrate was treated with Indion resin (20 ml)
to bring its pH to 2-3. The filtrate was again passed through a
column of IR-400 resin and then passed over a column of activated
carbon (5 g). The percentage color reduction was found to be the
same as reported in Table 3.
[0107] As illustrated above, all other materials indicated in
objectives and embodiments are found equally effective though not
illustrated by the examples.
[0108] Advantages of the present invention.
[0109] 1. The main advantage of the present invention is that the
said method is used for treating non-degradable lignin containing
effluents, since the disposal of such non-degradable lignin is
causing environmental problems.
[0110] 2. The treated water from this process can be recycled for
diluting further effluents for treating
[0111] 3. All the operations in this process are carried out at
room temperature, hence saves energy costs.
[0112] 4. The ion-exchange resins used in the process can be
regenerated and used for further treatment of water.
[0113] Further advantages of the present invention include: (1) the
process of the present invention is cost effective &
environment friendly; (2) it makes use of natural resources which
are degradable biologically and not harmful to the ecosystem; (3)
the process results in producing colorless, potable water which
meets all the environment control board stipulated standards; and
(4) the water thus produced either can be useful for recycling in
the process or let into the natural resources.
[0114] Additional advantages and modifications will readily occur
to those skilled in the art. Therefore, the invention in its
broader aspects is not limited to the specific details and
illustrative examples shown and described herein. Accordingly,
various modifications may be made without departing from the spirit
or scope of the general inventive concept as defined by the
appended claims and their equivalents.
* * * * *